Getaltheorie -- een inleiding

It is a complete rewrite of its predecessor, Getaltheorie voor beginners.
Apart from an elementary introduction a good number of chapters is devoted
to recent developments in elementary number theory. You can find the
pdf-file of the Preface and table of contents
here.

Pi

This is an introduction (again in Dutch, about 50 pages)
for high school students into the secrets of PI. It is issue 6
of the ZEBRA-series published jointly by Epsilon Uitgaven
and the Nederlandse Vereniging van Wiskundeleraren. ISBN-number is
90-5401-062-6. You
can find the pdf-file of the introduction and table of contents
here. As a result of repeated
requests you can find here the
answers to the exercises in pdf-format.